Telecentric fθ lens system for laser COM

ABSTRACT

A telecentric f theta  lens system for use in a laser COM comprising, from the object field side, a first lens unit including at least one negative lens component for generating a large negative distortion, a second lens unit consisting of one or two positive lens components for compensating spherical aberration and astigmatism generated by the first lens unit, a third lens unit including at least one positive lens component for providing a telecentric characteristic and a fourth lens unit including three or four lens components for providing a small F number.

This is a continuation of application Ser. No. 043,645, filed Apr. 28, 1987, now abandoned.

FIELD OF THE INVENTION

The present invention relates to a telecentric fθ lens system for a laser COM (Computer Output Microfilm) system, and more particularly to a telecentric fθ lens system having a tilting correction function therein or being capable of combination with a tilting correction lens unit.

BACKGROUND OF THE INVENTION

In laser scanning optics, a polygonal mirror or the like is used for scanning the laser beam. High speed rotation of the polygonal mirror causes the tilting of the deflecting or reflecting surface thereof and results in irregularity in the pitch of the scanning lines on a scanned surface. For eliminating the irregularity mentioned above, U.S. Pat. No. 3,750,189 has proposed an optical system for a laser printer in which the laser beam to be incident on the deflecting surface is formed in a line image and is restored after the deflection.

In the meantime, a laser COM system, in which microfilms are exposed by a laser beam modulated in accordance with data from a computer through an optical system including a polygonal mirror and fθ lens system, requires high dot density such as 9600 dots/inch for the recording on the microfilm of 15 mm in width. The high dot density requirement leads in an optical system with a short focal length of about 50 mm. The conventional optical systems with the tilting correction function for use in laser printers can not be adapted to the laser COM system since these optical systems have a long focal length, for example, 200 mm to 300 mm.

The high dot density requirement may be fulfilled by an optical system having a scanning lens system (fθ lens) and a reduction lens system which projects reduced images. However, this optical system has a drawback of large size.

Furthermore, a laser COM system for a high dot density recording requires a large aperture ratio for the optical system used therein to the extent of FNo.=3.

Japanese Laid-Open Patent Application No. 57-105715 discloses a telecentric fθ lens system with FNo.=3 for use in a laser COM system. However, the disclosed telecentric fθ lens system has no tilting correction function and can not be combined with the conventional tilting correction optics, because no space extends between the deflecting surface and the recording surface. The telecentric lens system, in which parallel light rays are emitted if the light rays come into the lens system from the focal point thereof, is thought to be suitable for the laser COM.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide an improved telecentric fθ lens system for use in a laser COM of a high dot density recording.

Another object of the present invention is to provide a telecentric fθ lens system for use in a laser COM of high dot density recording and being compact in size.

Still another object of the present invention is to provide a telecentric fθ lens system for use in a laser COM of a high dot density recording and having a small F number.

Still another object of the present invention is to provide a telecentric fθ lens system for use in a laser COM, being compact in size and having small F number.

Still another object of the present invention is to provide a telecentric fθ lens system for use in a laser COM of a high dot density recording and being capable of combination with a tilting correction lens system.

Still another object of the present invention is to provide a telecentric fθ lens system for use in a laser COM of a high dot density recording and having a tilting correction function therein.

These and other objects of the present invention can be fulfilled by a telecentric fθ lens system for use in a laser COM comprising, from the object field side, a first lens unit includng at least one negative lens component for generating large negative distortion to guarantee proper fθ characteristic, a second lens unit consisting of one or two positive lens component for compensating any spherical aberration and astigmatism generated by the first lens unit, a third lens unit including at least one positive lens component for providing a telecentric characteristic, and a fourth lens unit including three or four lens components for providing a small F number.

The telecentric fθ lens system of the present invention mentioned above can be used in combination with a polygonal mirror with a low accuracy of rotatation and a tilting correction lens system which includes a first cylindrical lens disposed between a laser beam source and a polygonal mirror and a second cylindrical lens disposed between the telecentric fθ lens system and the recording surface, or in combination with a polygonal mirror with a high accuracy of rotation.

Further, the above mentioned telecentric fθ lens system of the present invention can be constructed to suit a telecentric fθ lens system with an additional tilting correction function added by some modification, namely adding a fifth lens unit of an anamorphic characteristic in which a refractive power in the sagittal direction is larger than that in the meridional direction and putting the lens surface of the third and/or fourth lens unit in an anamorphic surface.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and advantages thereof, may best be understood by reference to the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically showing a laser COM in which a first to sixteenth embodiment are to be used;

FIGS. 2a to 17a are diagrams in section showing the telecentric fθ lens system of the first to sixteenth embodiments;

FIGS. 2b to 17b are diagrams showing aberration curves of the first to sixteenth embodiments;

FIG. 18 is a diagram schematically showing a laser COM in which a seventeenth to twenty-eighth embodiment are to be used;

FIGS. 19a to 30a are diagrams in meridional section showing the telecentric fθ lens system of the seventeenth to twenty-eighth embodiments;

FIGS. 19b to 30b are diagrams in sagittal section showing the telecentric fθ lens system of the seventeenth to twenty-eighth embodiments; and

FIGS. 19c to 30c are diagrams showing aberration curves of the seventeenth to twenty-eighth embodiments.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is provided to enable any person skilled in the optical art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein specifically to provide a telecentric fθ lens system.

In the accompanying drawings which supplement the following tables, the lenses in accordance with the present invention are diagrammatically from the object field side (left side in the drawings) to the image field side (right side in the drawings).

The radii of curvature of the lenses are indicated by r, with a subscript (abscript number) corresponding to consecutive numbers of the lenses. The axial distances, d, along the optical axis are set forth in the tables and include both the axial spacings between the lenses and the thickness of the lenses. Finally, various data in sagittal and meridional directions are distinguished by subscript "S" and "M".

A first type of the telecentric fθ lens system will be explained hereinafter with reference to FIGS. 1 to 17.

In FIG. 1, a laser beam B which is modulated in accordance with data from a computer is projected onto a raw microfilm 1 through a first cylindrical lens 2, the polygonal mirror 3, the telecentric fθ lens system 4 and a second cylindrical lens 5. The first and second cylindrical lenses 3 and 5 function as the tilting correction optics. The telecentric fθ lens system 4 is disposed so that the aperture stop position of the lens system 4 coincides with the deflecting surface of the polygonal mirror 1.

Referring to FIGS. 2a to 17a, a construction of the telecentric fθ lens system 4 will be explained hereinafter. The lens system 4 comprises, from the object field side, an aperture stop S, a first lens unit I including at least one negative lens component, a second lens unit II consisting of one or two positive lens component, a third lens unit III including at least one positive lens component and a fourth lens unit IV including three or four lens components. Each lens unit peforms the following functions. The first lens unit I generates large negative distortion to guarantee a proper fθ characteristic. The second lens unit II compensates for the spherical aberration and the astigmatism generated by the first unit I in some degree and contributes to the formation of a fθ lens with a small F number. The third lens unit III effects to form a telecentric system, namely to form a fθ lens being almost telecentric and having small F number in cooperation with the first and second lens units I and II. The fourth lens unit IV effects to achieve a small F number, i.e., F=3 and amends mainly the coma aberratiin and the curvature of field. Respective lens units of course, cooperate with each other to give a satisfactory property to the whole lens system.

More particularly, it is preferable for the fourth lens unit IV to be constituted from three lenses of posi-nega-posi or four lenses of posi-posi-nega-posi. In this case it is easy to keep the off-axis aberration under control.

Further, the fθ lens system keeps satisfactory balance between each of the aberrations if the following conditions are fulfilled:

(1) 0≦f/r_(A) <1

(2) 0.6<f/r_(B) <1

(3) 0≦-f/r_(C) <1

(4) 0.4<f/d_(D) <0.7

wherein f is a total focal length of the lens system, r_(A) is a radius of curvature of the image field side surface of the negative lens in the first lens unit I, r_(B) is a radius of curvature of the object field side surface of the positive lens in the third lens unit III, r_(C) is a radius of curvature of the object field side surface of the negative lens in the fourth lens unit IV and d_(D) is an axial distance of the whole lens system.

The condition (1) is provided for generating large negative distortion to give a proper fθ characteristic. If the upper limit of the condition (1) is violated, the distortion becomes excessively generated. On the other hand, if the lower limit of the condition (1) is violated, it is difficult to control the amount of the aberrations.

The condition (2) is provided for amending the off-axis aberrations, especially, the astigmatism and distortion to guarantee a large aperture ratio. If the upper limit of the condition (2) is violated, it becomes difficult to amend the astigmatism. While it becomes difficult to amend the distortion if the lower limit of the condition (2) is violated.

The condition (3) is provided for fully amending the spherical and coma aberrations generated by other lens units. If the upper limit of the condition (3) is violated, the amounts of the spherical and coma aberrations become excessively larger. On the other hand, if the lower limit of the condition (3) is violated, the amounts of the spherical and coma aberrations become undesirably smaller.

The condition (4) defines the length of the whole lens system. If the upper limit of the condition (4) is violated, the space between the polygonal mirror and the lens system becomes so small as not to maintain a beam scanning construction. On the other hand, if the lower limit of the condition (4) is violated, the space between the lens system and the image surface becomes so small as not to dipose another mechanism or lens system. Namely, the compactness of the whole lens system is deteriorated, if the condition (4) is not fulfilled.

Next, the second type of the telecentric fθ lens system according to the present invention will be explained by referring to FIGS. 18 to 30.

FIG. 18 shows a laser COM system in which the second type lens system is embodied. The laser COM system is similar to the system illustrated in FIG. 1 except for the lack of the second cylindrical lens 5 since the telecentric fθ lens system 4' of the second type has the tilting correction function therein instead of the second cylindrical lens.

Referring to FIGS. 19a to 30a and 19b to 30b, a construction of the second type telecentric fθ lens system 4' comprises, for the object field side, an aperture stop S', and a first lens unit I' including at least one negative lens component, a second lens unit II' consisting of one or two positive lens components, a third lens unit III' including at least one positive lens component, a fourth lens unit IV' including three or more lens components and a fifth lens unit V' of an anamorphic characteristic in which a refractive power of the fifth lens unit V in the sagittal direction is larger than that in the meridional direction, wherein the third and/or fourth lens unit has at least one anamorphic surface. The lens units I' to IV' perform the same functions as described in the previous explanation of the first type lens system. The fifth lens unit V guarantees the magnification βs in the sagittal direction. In addition the anamorphic surface(s) formed on the lens surface of the third and/or fourth lens units is provided to maintain the power in the sagittal direction in a proper degree and to amend the astigmatism of the sagittal direction, namely, to guarantee the adequate flatness of the image plane. Of course, respective lens units cooperate with each other to give a satisfactory property to the whole lens system.

Especially, if the following conditions are fulfilled, the lens design becomes flexible.

f_(S) <f_(M)

0.4<-β_(S) <0.8

wherein,

f_(S) : a focal length of the sagittal direction

f_(M) : a focal length of the meridional direction

β_(S) : a magnification of the sagittal direction

Furthermore, the fθ lens system of the second type keeps a satsifactory balance between each aberration if the conditions (1) to (4) are maintained as previously explained.

The telecentrix fθ system according to the present invention is preferable to a laser COM system of a high dot density recording such as 9600 dots/inch because of the small F number, to put it concretely, FNo.=3.0. Furthermore, the telecentric fθ lens system according to the present invention can be made in a compact size.

The following tables show lens data of respective embodiments in which the refractive index N is a value at λ=632.8 nm, and 2ω represents an angle of view. With respect to the seventeenth to twenty-eighth embodiments, the symbols represent the following parameters:

f_(M) : focal length in the meridional direction

β_(M) : magnification in the meridional direction;

FNo._(M) : F number in the meridional direction;

2ω_(M) : angle of view in the meridional direction;

f_(S) : focal length in the sagittal direction;

β_(S) : magnification in the sagittal direction;

eff.FNo._(S) : effective F number in the sagittal direction.

Additionally, each of the tables show the values of conditions (1) to (4).

The lens system can further be defined by the following conditions:

0≦f_(M) /r_(A) <1

0.6<f_(M) /r_(B) <1

0≦-f_(M) /r_(C) <1

0.4<f_(M) /r_(D) <0.6

wherein f_(M) is a total focal length of the lens system in the meridional direction, r_(A) is a radius of curvature of the image field side surface of the negative lens in the first lens unit I, r_(B) is a radius of curvature of the object field side surface of the positive lens in the third lens unit III, r_(C) is a radius of curvature of the object field side surface of the negative lens in the fourth lens unit IV and d_(D) is an axial distance of the whole lens system.

                  TABLE 1                                                          ______________________________________                                         f = 50 mm FNo. = 3.0 2ω = 20° λ = 632.8 nm                 radius of         axial         refractive                                     curvature         distance      index                                          ______________________________________                                         r.sub.1                                                                               (stop)         d.sub.1                                                                            21.461                                               r.sub.2                                                                               -108.861       d.sub.2                                                                            3.000     n.sub.1                                                                            1.51508                                r.sub.3                                                                               -68.207        d.sub.3                                                                            2.500                                                r.sub.4                                                                               -28.749        d.sub.4                                                                            2.500     n.sub.2                                                                            1.51508                                r.sub.5                                                                               81.065         d.sub.5                                                                            9.800                                                r.sub.6                                                                               -121.077       d.sub.6                                                                            3.800     n.sub.3                                                                            1.51508                                r.sub.7                                                                               -51.016        d.sub.7                                                                            1.000                                                r.sub.8                                                                               233.872        d.sub.8                                                                            5.500     n.sub.4                                                                            1.74969                                r.sub.9                                                                               -75.441        d.sub.9                                                                            11.800                                               r.sub.10                                                                              73.191         d.sub.10                                                                           5.500     n.sub.5                                                                            1.74969                                r.sub.11                                                                              -406.367       d.sub.11                                                                           10.400                                               r.sub.12                                                                              217.151        d.sub.12                                                                           4.000     n.sub.6                                                                            1.74969                                r.sub.13                                                                              -238.979       d.sub.13                                                                           1.800                                                r.sub.14                                                                              68.249         d.sub.14                                                                           3.600     n.sub.7                                                                            1.74969                                r.sub.15                                                                              -553.879       d.sub.15                                                                           4.200                                                r.sub.16                                                                              -94.861        d.sub.16                                                                           2.800     n.sub.8                                                                            1.74969                                r.sub.17                                                                              29.740         d.sub.17                                                                           4.200                                                r.sub.18                                                                              323.347        d.sub.18                                                                           4.200     n.sub.9                                                                            1.74969                                r.sub.19                                                                              -140.240       Σd                                                                           102.061       (s' = 27.538)                          f/r.sub.A = f/r.sub.5 = 0.62, f/r.sub.B = f/r.sub.10 = 0.68,                   -f/r.sub.C = -f/r.sub.16 = 0.53, f/d.sub.D = 0.68                              ______________________________________                                    

                  TABLE 2                                                          ______________________________________                                         f = 50 mm FNo. = 3.0 2ω = 20° λ = 632.8 nm                 radius of         axial         refractive                                     curvature         distance      index                                          ______________________________________                                         r.sub.1                                                                               (stop)         d.sub.1                                                                            22.814                                               r.sub.2                                                                               -31.371        d.sub.2                                                                            2.500     n.sub.1                                                                            1.51508                                r.sub.3                                                                               87.656         d.sub.3                                                                            8.575                                                r.sub.4                                                                               -52.182        d.sub.4                                                                            3.302     n.sub.2                                                                            1.51508                                r.sub.5                                                                               -38.133        d.sub.5                                                                            0.717                                                r.sub.6                                                                               214.112        d.sub.6                                                                            5.479     n.sub.3                                                                            1.74969                                r.sub.7                                                                               -78.975        d.sub.7                                                                            12.345                                               r.sub.8                                                                               71.303         d.sub.8                                                                            10.911    n.sub.4                                                                            1.74969                                r.sub.9                                                                               -399.439       d.sub.9                                                                            14.374                                               r.sub.10                                                                              160.273        d.sub.10                                                                           4.708     n.sub.5                                                                            1.74969                                r.sub.1l                                                                              -299.186       d.sub.11                                                                           4.154                                                r.sub.12                                                                              62.840         d.sub.12                                                                           3.453     n.sub.6                                                                            1.74969                                r.sub.13                                                                              -513.236       d.sub.13                                                                           3.190                                                r.sub.14                                                                              -83.279        d.sub.14                                                                           3.166     n.sub.7                                                                            1.74969                                r.sub.15                                                                              31.226         d.sub.15                                                                           3.649                                                r.sub.16                                                                              256.708        d.sub.16                                                                           2.798     n.sub.8                                                                            1.74969                                r.sub.17                                                                              -125.883       Σd                                                                           106.135       (s' = 26.493)                          f/r.sub.A = f/r.sub.3 = 0.57, f/r.sub.B = f/r.sub.8 = 0.70,                    -f/r.sub.C = -f/r.sub.14 = 0.60, f/d.sub.D = 0.60                              ______________________________________                                    

                  TABLE 3                                                          ______________________________________                                         f = 50 mm FNo. = 3.0 2ω = 20° λ = 632.8 nm                 radius of         axial         refractive                                     curvature         distance      index                                          ______________________________________                                         r.sub.1                                                                               (stop)         d.sub.1                                                                            22.713                                               r.sub.2                                                                               -31.047        d.sub.2                                                                            2.494     n.sub.1                                                                            1.51508                                r.sub.3                                                                               76.304         d.sub.3                                                                            8.579                                                r.sub.4                                                                               -51.692        d.sub.4                                                                            3.739     n.sub.2                                                                            1.51508                                r.sub.5                                                                               -38.767        d.sub.5                                                                            0.843                                                r.sub.6                                                                               196.465        d.sub.6                                                                            5.372     n.sub.3                                                                            1.74969                                r.sub.7                                                                               -72.870        d.sub.7                                                                            11.684                                               r.sub.8                                                                               67.826         d.sub.8                                                                            7.319     n.sub.4                                                                            1.51508                                r.sub.9                                                                               -256.797       d.sub.9                                                                            14.054                                               r.sub.10                                                                              112.614        d.sub.10                                                                           5.486     n.sub.5                                                                            1.74969                                r.sub.11                                                                              -235.723       d.sub.11                                                                           6.599                                                r.sub.12                                                                              63.720         d.sub.12                                                                           4.772     n.sub.6                                                                            1.80094                                r.sub.13                                                                              -450.816       d.sub.13                                                                           2.825                                                r.sub.14                                                                              -88.744        d.sub.14                                                                           3.522     n.sub.7                                                                            1.80094                                r.sub.15                                                                              31.661         d.sub.15                                                                           2.989                                                r.sub.16                                                                              2140.319       d.sub.16                                                                           3.520     n.sub.8                                                                            1.80094                                r.sub.17                                                                              -96.036        Σd                                                                           106.510       (s' = 27.343)                          f/r.sub.A = f/r.sub.3 = 0.66, f/r.sub.B = f/r.sub.8 = 0.74,                    -f/r.sub.C = -f/r.sub.14 = 0.56, f/d.sub.D = 0.60                              ______________________________________                                    

                  TABLE 4                                                          ______________________________________                                         f = 50 mm FNo. = 3.0 2ω = 20° λ = 632.8 nm                 radius of         axial         refractive                                     curvature         distance      index                                          ______________________________________                                         r.sub.1                                                                              (stop)          d.sub.1                                                                            20.857                                               2.sub.2                                                                              -31.539         d.sub.2                                                                            2.500     n.sub.1                                                                            1.51508                                r.sub.3                                                                              105.988         d.sub.3                                                                            8.126                                                r.sub.4                                                                              -54.128         d.sub.4                                                                            3.503     n.sub.2                                                                            1.51508                                r.sub.5                                                                              -37.151         d.sub.5                                                                            0.276                                                r.sub.6                                                                              192.719         d.sub.6                                                                            5.225     n.sub.3                                                                            1.74969                                r.sub.7                                                                              -81.249         d.sub.7                                                                            8.519                                                r.sub.8                                                                              71.888          d.sub.8                                                                            12.730    n.sub.4                                                                            1.51508                                r.sub.9                                                                              -240.080        d.sub.9                                                                            24.991                                               r.sub.10                                                                             133.966         d.sub.10                                                                           2.394     n.sub.5                                                                            1.74969                                r.sub.11                                                                             -244.943        d.sub.11                                                                           3.313                                                r.sub.12                                                                             66.688          d.sub.12                                                                           2.232     n.sub.6                                                                            1.80094                                r.sub.13                                                                             -1331.310       d.sub.13                                                                           6.313                                                r.sub.14                                                                             -71.862         d.sub.14                                                                           1.636     n.sub.7                                                                            1.51508                                r.sub.15                                                                             27.248          d.sub.15                                                                           4.000                                                r.sub.16                                                                             289.706         d.sub.16                                                                           2.645     n.sub.8                                                                            1.80094                                r.sub.17                                                                             -244.926        Σd                                                                           109.260       (s' = 19.945)                          f/r.sub.A = f/r.sub.3 = 0.47, f/r.sub.B = f/r.sub.8 = 0.70 -f/r.sub.C =        -f/r.sub.14 = 0.70, f/d.sub.D = 0.57                                           ______________________________________                                    

                  TABLE 5                                                          ______________________________________                                         f = 50 mm FNo. = 3.0 2ω = 20° λ = 632.8 nm                 radius of         axial         refractive                                     curvature         distance      index                                          ______________________________________                                         r.sub.1                                                                              (stop)          d.sub.1                                                                            33.081                                               r.sub.2                                                                              -25.957         d.sub.2                                                                            2.500     n.sub.1                                                                            1.51508                                r.sub.3                                                                              "               d.sub.3                                                                            8.304                                                r.sub.4                                                                              -78.759         d.sub.4                                                                            3.374     n.sub.2                                                                            1.51508                                r.sub.5                                                                              -36.700         d.sub.5                                                                            0.930                                                r.sub.6                                                                              528.572         d.sub.6                                                                            5.414     n.sub.3                                                                            1.74969                                r.sub.7                                                                              -81.957         d.sub.7                                                                            12.862                                               r.sub.8                                                                              63.416          d.sub.8                                                                            6.927     n.sub.4                                                                            1.74969                                r.sub.9                                                                              -454.190        d.sub.9                                                                            14.654                                               r.sub.10                                                                             167.864         d.sub.10                                                                           4.301     n.sub.5                                                                            1.74969                                r.sub.11                                                                             -368.568        d.sub.11                                                                           6.236                                                r.sub.12                                                                             61.102          d.sub.12                                                                           3.905     n.sub.6                                                                            1.74969                                r.sub.13                                                                             1119.207        d.sub.13                                                                           1.739                                                r.sub.14                                                                             -81.478         d.sub.14                                                                           3.130     n.sub.7                                                                            1.74969                                r.sub.15                                                                             29.529          d.sub.15                                                                           2.594                                                r.sub.16                                                                             102.790         d.sub.16                                                                           3.605     n.sub.8                                                                            1.74969                                r.sub.17                                                                             -3666.078       Σd                                                                           113.556       (s' = 19.278)                          f/r.sub.A = f/r.sub.3 = 0 f/r.sub.B = f/r.sub.8 = 0.79,                        -f/r.sub.C = -f/r.sub.14 = 0.61, f/d.sub.D = 0.62                              ______________________________________                                    

                  TABLE 6                                                          ______________________________________                                         f = 50 mm FNo. = 3.0 2ω = 20° λ = 632.8 nm                 radius of         axial         refractive                                     curvature         distance      index                                          ______________________________________                                         r.sub.1                                                                               (stop)         d.sub.1                                                                            18.461                                               r.sub.2                                                                               -29.916        d.sub.2                                                                            2.500     n.sub.1                                                                            1.51508                                r.sub.3                                                                               80.521         d.sub.3                                                                            8.849                                                r.sub.4                                                                               -48.446        d.sub.4                                                                            4.519     n.sub.2                                                                            1.51508                                r.sub.5                                                                               -38.780        d.sub.5                                                                            0.299                                                r.sub.6                                                                               216.418        d.sub.6                                                                            5.414     n.sub.3                                                                            1.74969                                r.sub.7                                                                               -62.043        d.sub.7                                                                            12.630                                               r.sub.8                                                                               70.049         d.sub.8                                                                            6.927     n.sub.4                                                                            1.74969                                r.sub.9                                                                               -462.550       d.sub.9                                                                            18.377                                               r.sub.10                                                                              65.961         d.sub.10                                                                           6.637     n.sub.5                                                                            1.74969                                r.sub.11                                                                              -264.210       d.sub.11                                                                           4.405                                                r.sub.12                                                                              -93.256        d.sub.12                                                                           2.387     n.sub.6                                                                            1.74969                                r.sub.13                                                                              32.887         d.sub.13                                                                           5.313                                                r.sub.14                                                                              179.107        d.sub.14                                                                           2.580     n.sub.7                                                                            1.74969                                r.sub.15                                                                              -76.677        Σd                                                                           99.298        (s' =  28.312)                         f/r.sub.A = f/r.sub.3 = 0.62, f/r.sub.B = f/r.sub.8 = 0.81,                    -f/r.sub.C = -f/r.sub.12 = 0.54, f/d.sub.D = 0.62                              ______________________________________                                    

                  TABLE 7                                                          ______________________________________                                         f = 50 mm FNo. = 3.0 2ω = 20° λ = 632.8 nm                 radius of         axial         refractive                                     curvature         distance      index                                          ______________________________________                                         r.sub.1                                                                               (stop)         d.sub.1                                                                            20.420                                               r.sub.2                                                                               -29.253        d.sub.2                                                                            2.500     n.sub.1                                                                            1.51508                                r.sub.3                                                                               81.494         d.sub.3                                                                            5.820                                                r.sub.4                                                                               -56.324        d.sub.4                                                                            7.408     n.sub.2                                                                            1.51508                                r.sub.5                                                                               -39.509        d.sub.5                                                                            0.012                                                r.sub.6                                                                               115.612        d.sub.6                                                                            5.414     n.sub.3                                                                            1.51508                                r.sub.7                                                                               -54.138        d.sub.7                                                                            9.995                                                r.sub.8                                                                               57.246         d.sub.8                                                                            6.927     n.sub.4                                                                            1.61052                                r.sub.9                                                                               -292.997       d.sub.9                                                                            16.896                                               r.sub.10                                                                              67.687         d.sub.10                                                                           6.637     n.sub.5                                                                            1.74969                                r.sub.11                                                                              -350.764       d.sub.11                                                                           3.153                                                r.sub.12                                                                              -74.159        d.sub.12                                                                           2.387     n.sub.6                                                                            1.51508                                r.sub.13                                                                              28.396         d.sub.13                                                                           4.811                                                r.sub.14                                                                              229.052        d.sub.14                                                                           2.580     n.sub.7                                                                            1.74969                                r.sub.15                                                                              -103.592       Σd                                                                           94.960        (s' =  31.563)                         f/r.sub.A = f/r.sub.3 = 0.61, f/r.sub.B = f/r.sub.8 = 0.87,                    -f/r.sub.C = -f/r.sub.12 = 0.67, f/d.sub.D = 0.67                              ______________________________________                                    

                  TABLE 8                                                          ______________________________________                                                     FNo. = 3.0                                                         f = 50 mm   2ω = 20°                                                                       λ = 632.8 nm                                   radius of   axial        refractive                                            curvature   distance     index                                                 ______________________________________                                         r.sub.1                                                                              (stop)    d.sub.1 18.387                                                 r.sub.2                                                                              -28.368   d.sub.2 2.489  n.sub.1                                                                             1.51508                                    r.sub.3                                                                              71.718    d.sub.3 6.889                                                  r.sub.4                                                                              -53.394   d.sub.4 9.714  n.sub.2                                                                             1.51508                                    r.sub.5                                                                              -39.242   d.sub.5 0.012                                                  r.sub.6                                                                              141.442   d.sub.6 6.156  n.sub.3                                                                             1.51508                                    r.sub.7                                                                              -52.965   d.sub.7 10.082                                                 r.sub.8                                                                              53.299    d.sub.8 6.927  n.sub.4                                                                             1.74969                                    r.sub.9                                                                              -386.460  d.sub.9 18.525                                                 r.sub.10                                                                             57.416    d.sub.10                                                                               6.637  n.sub.5                                                                             1.51508                                    r.sub.11                                                                             -224.512  d.sub.11                                                                               1.500                                                  r.sub.12                                                                             -67.889   d.sub.12                                                                               2.387  n.sub.6                                                                             1.80094                                    r.sub.13                                                                             34.006    d.sub.13                                                                               6.638                                                  r.sub.14                                                                             200.683   d.sub.14                                                                               2.800  n.sub.7                                                                             1.74969                                    r.sub.15                                                                             -61.727   Σd                                                                               99.143      (s' = 30.167)                              f/r.sub.A = f/r.sub.3 = 0.70, f/r.sub.B = f/r.sub.8 = 0.94, -f/r.sub.C =       -f/r.sub.12 = 0.74,                                                            f/d.sub.D = 0.62                                                               ______________________________________                                    

                  TABLE 9                                                          ______________________________________                                                     FNo. = 3.0                                                         f = 50 mm   2ω = 20°                                                                       λ = 632.8 nm                                   radius of   axial        refractive                                            curvature   distance     index                                                 ______________________________________                                         r.sub.1                                                                              (stop)    d.sub.1 22.258                                                 r.sub.2                                                                              -27.716   d.sub.2 2.444  n.sub.1                                                                             1.51508                                    r.sub.3                                                                              103.345   d.sub.3 9.000                                                  r.sub.4                                                                              -65.055   d.sub.4 4.222  n.sub.2                                                                             1.51508                                    r.sub.5                                                                              -43.803   d.sub.5 0.333                                                  r.sub.6                                                                              310.922   d.sub.6 5.556  n.sub.3                                                                             1.74969                                    r.sub.7                                                                              -56.436   d.sub.7 12.556                                                 r.sub.8                                                                              63.645    d.sub.8 6.889  n.sub.4                                                                             1.74969                                    r.sub.9                                                                              -805.257  d.sub.9 16.289                                                 r.sub.10                                                                             87.374    d.sub.10                                                                               6.667  n.sub.5                                                                             1.74969                                    r.sub.11                                                                             ∞   d.sub.11                                                                               6.489                                                  r.sub.12                                                                             -100.649  d.sub.12                                                                               2.333  n.sub.6                                                                             1.74969                                    r.sub.13                                                                             33.706    d.sub.13                                                                               2.556                                                  r.sub.14                                                                             104.231   d.sub.14                                                                               3.556  n.sub.7                                                                             1.74969                                    r.sub.15                                                                             -79.194   Σd                                                                               101.148     (s' = 26.909)                              f/r.sub.A = f/r.sub.3 = 0.48, f/r.sub.B = f/r.sub.8 = 0.79, -f/r.sub.C =       -f/r.sub.12 = 0.50,                                                            f/d.sub.D = 0.63                                                               ______________________________________                                    

                  TABLE 10                                                         ______________________________________                                                     FNo. = 3.0                                                         f = 50 mm   2ω = 20°                                                                       λ = 632.8 nm                                   radius of   axial        refractive                                            curvature   distance     index                                                 ______________________________________                                         r.sub.1                                                                              (stop)    d.sub.1 23.057                                                 r.sub.2                                                                              -26.862   d.sub.2 2.444  n.sub.1                                                                             1.51508                                    r.sub.3                                                                              102.079   d.sub.3 9.000                                                  r.sub.4                                                                              -117.212  d.sub.4 5.543  n.sub.2                                                                             1.51508                                    r.sub.5                                                                              -51.567   d.sub.5 0.401                                                  r.sub.6                                                                              375.326   d.sub.6 5.730  n.sub.3                                                                             1.74969                                    r.sub.7                                                                              -51.644   d.sub.7 11.423                                                 r.sub.8                                                                              62.379    d.sub.8 7.274  n.sub.4                                                                             1.74969                                    r.sub.9                                                                              195.408   d.sub.9 17.876                                                 r.sub.10                                                                             63.504    d.sub.10                                                                               6.667  n.sub.5                                                                             1.74969                                    r.sub.11                                                                             209.685   d.sub.11                                                                               7.301                                                  r.sub.12                                                                             ∞   d.sub.12                                                                               3.500  n.sub.6                                                                             1.74969                                    r.sub.13                                                                             28.934    d.sub.13                                                                               2.000                                                  r.sub.14                                                                             57.507    d.sub.14                                                                               3.556  n.sub.7                                                                             1.74969                                    r.sub.15                                                                             -261.844  Σd                                                                               105.772     (s'= 24.888)                               f/r.sub.A = f/r.sub.3 = 0.49, f/r.sub.B = f/r.sub.6 = 0.80, -f/r.sub.C =       -f/r.sub.12 =  0,                                                              f/d.sub.D = 0.60                                                               ______________________________________                                    

                  TABLE 11                                                         ______________________________________                                                     FNo. = 3.0                                                         f = 50 mm   2ω = 20°                                                                       λ = 632.8 nm                                   radius of   axial        refractive                                            curvature   distance     index                                                 ______________________________________                                         r.sub.1                                                                              (stop)    d.sub.1 23.594                                                 r.sub.2                                                                              -27.750   d.sub.2 2.444  n.sub.1                                                                             1.51508                                    r.sub.3                                                                              128.499   d.sub.3 9.000                                                  r.sub.4                                                                              -80.501   d.sub.4 4.222  n.sub.2                                                                             1.51508                                    r.sub.5                                                                              -46.164   d.sub.5 0.333                                                  r.sub.6                                                                              ∞   d.sub.6 5.556  n.sub.3                                                                             1.74969                                    r.sub.7                                                                              -54.852   d.sub.7 12.556                                                 r.sub.8                                                                              55.331    d.sub.8 6.889  n.sub.4                                                                             1.74969                                    r.sub.9                                                                              ∞   d.sub.9 16.720                                                 r.sub.10                                                                             97.955    d.sub.10                                                                               6.667  n.sub.5                                                                             1.74969                                    r.sub.11                                                                             -187.259  d.sub.11                                                                               5.656                                                  r.sub.12                                                                             -70.601   d.sub.12                                                                               2.333  n.sub.6                                                                             1.74969                                    r.sub.13                                                                             33.075    d.sub.13                                                                               2.494                                                  r.sub.14                                                                             100.999   d.sub.14                                                                               3.556  n.sub.7                                                                             1.74969                                    r.sub.15                                                                             -86.274   Σd                                                                               102.020     (s' = 26.411)                              f/r.sub.A = f/r.sub.3 = 0.39, f/r.sub.B = f/r.sub.8 = 0.9, -f/r.sub.C =        -f/r.sub. 12 = 0.71,                                                           f/d.sub.D = 0.64                                                               ______________________________________                                    

                  TABLE 12                                                         ______________________________________                                                     FNo. = 3.0                                                         f = 50 mm   2ω = 20°                                                                       λ = 632.8 nm                                   radius of   axial        refractive                                            curvature   distance     index                                                 ______________________________________                                         r.sub.1                                                                              (stop)    d.sub.1 20.176                                                 r.sub.2                                                                              -40.250   d.sub.2 2.498  n.sub.1                                                                             1.51508                                    r.sub.3                                                                              53.272    d.sub.3 10.296                                                 r.sub.4                                                                              123.449   d.sub.4 5.153  n.sub.2                                                                             1.74969                                    r.sub.5                                                                              -72.065   d.sub.5 15.676                                                 r.sub.6                                                                              69.492    d.sub.6 11.147 n.sub.3                                                                             1.74969                                    r.sub.7                                                                              -398.267  d.sub.7 21.180                                                 r.sub.8                                                                              129.717   d.sub.8 5.450  n.sub.4                                                                             1.74969                                    r.sub.9                                                                              -227.550  d.sub.9 2.402                                                  r.sub.10                                                                             56.615    d.sub.10                                                                               8.334  n.sub.5                                                                             1.74969                                    r.sub.11                                                                             -2234.934 d.sub.11                                                                               2.300                                                  r.sub.12                                                                             -62.389   d.sub.12                                                                               2.913  n.sub.6                                                                             1.74969                                    r.sub.13                                                                             32.672    d.sub.13                                                                               4.948                                                  r.sub.14                                                                             65.931    d.sub.14                                                                               3.657  n.sub.7                                                                             1.74969                                    r.sub.15                                                                             667.179   Σd                                                                               116.130     (s' = 19.952)                              f/r.sub.A = f/r.sub.3 = 0.94, f/r.sub.B = f/r.sub.6 = 0.72, -f/r.sub.C =       -f/r.sub.12 =  0.80,                                                           f/d.sub.D = 0.52                                                               ______________________________________                                    

                  TABLE 13                                                         ______________________________________                                                     FNo. = 3.0                                                         f = 50 mm   2ω = 20°                                                                       λ = 632.8 nm                                   radius of   axial        refractive                                            curvature   distance     index                                                 ______________________________________                                         r.sub.1                                                                              (stop)    d.sub.1 15.269                                                 r.sub.2                                                                              -33.434   d.sub.2 2.502  n.sub.1                                                                             1.51508                                    r.sub.3                                                                              54.783    d.sub.3 11.645                                                 r.sub.4                                                                              315.383   d.sub.4 5.024  n.sub.2                                                                             1.74969                                    r.sub.5                                                                              -52.630   d.sub.5 13.575                                                 r.sub.6                                                                              71.581    d.sub.6 5.957  n.sub.3                                                                             1.74969                                    r.sub.7                                                                              -193.478  d.sub.7 22.548                                                 r.sub.8                                                                              61.869    d.sub.8 4.769  n.sub.4                                                                             1.74969                                    r.sub.9                                                                              -237.209  d.sub.9 6.500                                                  r.sub.10                                                                             -68.707   d.sub.10                                                                               1.615  n.sub.5                                                                             1.74969                                    r.sub.11                                                                             33.684    d.sub.11                                                                               4.623                                                  r.sub.12                                                                             104.760   d.sub.12                                                                               3.623  n.sub.6                                                                             1.74969                                    r.sub.13                                                                             -81.195   Σd                                                                               97.950      (s' = 28.545)                              f/r.sub.A = f/r.sub.3 = 0.91, f/r.sub.B = f/r.sub.6 = 0.70, -f/r.sub.C =       -f/r.sub.10 = 0.73,                                                            f/d.sub.D = 0.60                                                               ______________________________________                                    

                  TABLE 14                                                         ______________________________________                                                     FNo. = 3.0                                                         f = 50 mm   2ω = 20°                                                                       λ = 632.8 nm                                   radius of   axial        refractive                                            curvature   distance     index                                                 ______________________________________                                         r.sub.1                                                                              (stop)    d.sub.1 13.604                                                 r.sub.2                                                                              -30.055   d.sub.2 2.502  n.sub.1                                                                             1.51508                                    r.sub.3                                                                              56.761    d.sub.3 11.509                                                 r.sub.4                                                                              243.775   d.sub.4 5.924  n.sub.2                                                                             1.51508                                    r.sub.5                                                                              -37.990   d.sub.5 10.049                                                 r.sub.6                                                                              72.876    d.sub.6 7.555  n.sub.3                                                                             1.51508                                    r.sub.7                                                                              -103.442  d.sub.7 22.709                                                 r.sub.8                                                                              50.111    d.sub.8 12.000 n.sub.4                                                                             1.80094                                    r.sub.9                                                                              -191.063  d.sub.9 4.763                                                  r.sub.10                                                                             -76.937   d.sub.10                                                                               13.683 n.sub.5                                                                             1.80094                                    r.sub.11                                                                             29.161    d.sub.11                                                                               7.487                                                  r.sub.12                                                                             75.759    d.sub.12                                                                               3.000  n.sub.6                                                                             1.80094                                    r.sub.13                                                                             -118.897  Σd                                                                               114.785     (s' = 21.652)                              f/r.sub.A = f/r.sub.3 = 0.88, f/r.sub.B = f/r.sub.6 = 0.69, -f/r.sub.C =       -f/r.sub.10 = 0.65                                                             f/d.sub.D = 0.49                                                               ______________________________________                                    

                  TABLE 15                                                         ______________________________________                                         f = 50 mm FNo. = 3.0 2ω = 20° λ = 632.8 nm                 radius of     axial      refractive                                            curvature     distance   index                                                 ______________________________________                                         r.sub.1                                                                               (stop)                                                                                    d.sub.1                                                                              22.617                                                 r.sub.2                                                                               -33.207                                                                                   d.sub.2                                                                              2.500  n.sub.1 1.74969                                 r.sub.3                                                                               78.287                                                                                    d.sub.3                                                                              9.419                                                  r.sub.4                                                                               671.114                                                                                   d.sub.4                                                                              5.664  n.sub.1 1.74969                                 r.sub.5                                                                               -48.067                                                                                   d.sub.5                                                                              4.171                                                  r.sub.6                                                                               62.808                                                                                    d.sub.6                                                                              11.055 n.sub.3 1.80094                                 r.sub.7                                                                               -130.359                                                                                  d.sub.7                                                                              20.203                                                 r.sub.8                                                                               69.332                                                                                    d.sub.8                                                                              5.911  n.sub.4 1.80094                                 r.sub.9                                                                               -105.416                                                                                  d.sub.9                                                                              1.500                                                  r.sub.10                                                                              -54.193                                                                                   d.sub.10                                                                             11.224 n.sub.5 1.80094                                 r.sub.11                                                                              34.186                                                                                    d.sub.11                                                                             1.980                                                  r.sub.12                                                                              76.402                                                                                    d.sub.12                                                                             3.623  n.sub.6 1.80094                                 r.sub.13                                                                              -120.484                                                                                  Σd                                                                             99.867 (s' = 33.357)                                   f/r.sub.A = f/r.sub.3 = 0.64, f/r.sub.B =  f/r.sub.6 = 0.80, --f/r.sub.C       = -f/r.sub.10 = 0.92, f/d.sub.D = 0.65                                         ______________________________________                                    

                  TABLE 16                                                         ______________________________________                                         f = 50 mm FNo. = 3.0 2ω= 20°λ= 632.8 nm                    radius of     axial      refractive                                            curvature     distance   index                                                 ______________________________________                                         r.sub.1                                                                               (stop)                                                                                    d.sub.1                                                                              16.408                                                 r.sub.2                                                                               -33.031                                                                                   d.sub.2                                                                              2.502  n.sub.1 1.51508                                 r.sub.3                                                                               56.070                                                                                    d.sub.3                                                                              11.187                                                 r.sub.4                                                                               209.177                                                                                   d.sub.4                                                                              5.251  n.sub.2 1.74969                                 r.sub.5                                                                               -50.166                                                                                   d.sub.5                                                                              13.606                                                 r.sub.6                                                                               66.646                                                                                    d.sub.6                                                                              15.412 n.sub.3 1.61052                                 r.sub.7                                                                               -187.673                                                                                  d.sub.7                                                                              26.245                                                 r.sub.8                                                                               55.420                                                                                    d.sub.8                                                                              8.189  n.sub.4 1.80094                                 r.sub.9                                                                               -228.445                                                                                  d.sub.9                                                                              5.372                                                  r.sub.10                                                                              -57.786                                                                                   d.sub.10                                                                             2.427  n.sub.5 1.74969                                 r.sub.11                                                                              34.122                                                                                    d.sub.11                                                                             4.298                                                  r.sub.12                                                                              90.415                                                                                    d.sub.12                                                                             1.600  n.sub.6 1.80094                                 r.sub.13                                                                              -117.172                                                                                  Σd                                                                             112.497                                                                               (s' = 20.395)                                   f/r.sub.A =f/r.sub.3 = 0.89, f/r.sub.B = f/r.sub.6 = 0.75, --f/r.sub. C =      -f/r.sub.10 = 0.87, f/d.sub.D = 0.52                                           ______________________________________                                    

                  TABLE 17                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0 FNo..sub.M = 3.0 2ω.sub.M =             20° f.sub.S = 23.377 mm                                                 β.sub.S = -0.542 eff. FNo..sub.S = 3.0 λ = 632.8 nm                radius of     axial      refractive                                            curvature     distance   index                                                 ______________________________________                                         r.sub.1 (stop)                                                                                   d.sub.1                                                                              19.315                                                 r.sub.2 -97.975                                                                                  d.sub.2                                                                              2.700  n.sub.1 1.51508                                 r.sub.3 -61.386                                                                                  d.sub.3                                                                              2.250                                                  r.sub.4 -25.874                                                                                  d.sub.4                                                                              2.250  n.sub.2 1.51508                                 r.sub.5 72.959                                                                                   d.sub.5                                                                              8.820                                                  r.sub.6 -108.969                                                                                 d.sub.6                                                                              3.420  n.sub.3 1.51508                                 r.sub.7 -45.915                                                                                  d.sub.7                                                                              0.900                                                  r.sub.8 210.485                                                                                  d.sub.8                                                                              4.950  n.sub.4 1.74969                                 r.sub.9 -97.896                                                                                  d.sub.9                                                                              10.620                                                 r.sub.10                                                                               65.872                                                                                   d.sub.10                                                                             4.950  n.sub.5 1.74969                                 r.sub.11                                                                               -365.730                                                                                 d.sub.11                                                                             9.360                                                  r.sub.12M                                                                              195.436                                                                r.sub.12S                                                                              84.044                                                                                   d.sub.12                                                                             3.600  n.sub.6 1.74969                                 r.sub.13M                                                                              -215.081                                                               r.sub.13S                                                                              -279.925                                                                                 d.sub.13                                                                             1.620                                                  r.sub.14                                                                               61.424                                                                                   d.sub.14                                                                             3.240  n.sub.7 1.74969                                 r.sub.15                                                                               -498.490                                                                                 d.sub.15                                                                             3.780                                                  r.sub.16                                                                               -85.375                                                                                  d.sub.16                                                                             2.520  n.sub.8 1.74969                                 r.sub.17                                                                               26.766                                                                                   d.sub.17                                                                             3.780                                                  r.sub.18                                                                               291.012                                                                                  d.sub.18                                                                             3.780  n.sub.9 1.74969                                 r.sub.19                                                                               -126.216                                                                                 d.sub.19                                                                             3.000                                                  r.sub.20M                                                                              ∞                                                                r.sub.20S                                                                              32.604                                                                                   d.sub.20                                                                             3.000  n.sub.10 1.80094                                r.sub.21M                                                                              ∞                                                                r.sub.21S                                                                              129.969                                                                                  d.sub.21                                                                             1.000                                                  r.sub.22M                                                                              ∞                                                                r.sub.22S                                                                              14.988                                                                                   d.sub.22                                                                             3.000  n.sub.11 1.80094                                r.sub.23M                                                                              ∞                                                                r.sub.23S                                                                              21.604                                                                                   Σd                                                                             101.855                                                                               (s' = 17.453)                                   f.sub.M /r.sub.A = f.sub.M /r.sub.5 = 0.62, f.sub.M /r.sub.B = f.sub.M         /r.sub.10 = 0.68,                                                              -f.sub.M /r.sub.C = -f.sub.M /r.sub.16 = 0.53, f.sub.M /d.sub.D  =             ______________________________________                                         0.55                                                                      

                  TABLE 18                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0 FNo..sub.M = 3.0 2ω.sub.M =             20° f.sub.S = 22.066 mm                                                 β.sub.S = -0.532 eff. FNo..sub.S = 3.0 λ = 632.8 nm                radius of     axial      refractive                                            curvature     distance   index                                                 ______________________________________                                         r.sub.1 (stop)                                                                                   d.sub.1                                                                              29.773                                                 r.sub.2 -23.362                                                                                  d.sub.2                                                                              2.250  n.sub.1 1.51508                                 r.sub.3 ∞                                                                                  d.sub.3                                                                              7.473                                                  r.sub.4 -70.883                                                                                  d.sub.4                                                                              3.037  n.sub.2 1.51508                                 r.sub.5 -33.030                                                                                  d.sub.5                                                                              0.837                                                  r.sub.6 475.715                                                                                  d.sub.6                                                                              4.872  n.sub.3 1.74969                                 r.sub.7 -73.761                                                                                  d.sub.7                                                                              11.576                                                 r.sub.8 57.075                                                                                   d.sub.8                                                                              6.234  n.sub.4 1.74969                                 r.sub.9 -408.771                                                                                 d.sub.9                                                                              13.188                                                 r.sub.10M                                                                              151.078                                                                r.sub.10S                                                                              46.037                                                                                   d.sub.10                                                                             3.871  n.sub.5 1.74969                                 r.sub.11M                                                                              -331.711                                                               r.sub.11S                                                                              637.906                                                                                  d.sub.11                                                                             5.613                                                  r.sub.12                                                                               54.992                                                                                   d.sub.12                                                                             3.514  n.sub.6 1.74969                                 r.sub.13                                                                               1007.283                                                                                 d.sub.13                                                                             1.565                                                  r.sub.14                                                                               -73.330                                                                                  d.sub.14                                                                             2.817  n.sub.7 1.74969                                 r.sub.15                                                                               26.576                                                                                   d.sub.15                                                                             2.355                                                  r.sub.16                                                                               92.511                                                                                   d.sub.16                                                                             3.244  n.sub.8 1.74969                                 r.sub.17                                                                               -3299.459                                                                                d.sub.17                                                                             1.000                                                  r.sub.18M                                                                              ∞                                                                r.sub.18S                                                                              10.223                                                                                   d.sub.18                                                                             3.068  n.sub.9 1.80094                                 r.sub.19M                                                                              ∞                                                                r.sub.19S                                                                              -366.741                                                                                 d.sub.19                                                                             0.500  n.sub.10 1.80094                                r.sub.20M                                                                              ∞                                                                r.sub.20S                                                                              -59.919                                                                                  d.sub.20                                                                             3.000                                                  r.sub.21M                                                                              ∞                                                                r.sub.21S                                                                              15.318                                                                                   Σd                                                                             109.767                                                                               (s' = 12.481)                                   f.sub.M /r.sub.A = f.sub.M /r.sub.3 = 0, f.sub.M /r.sub.B = f.sub.M            /r.sub.8 = 0.79,                                                               -f.sub.M /r.sub.C = -f.sub.M /r.sub.14 = 0.61, f.sub.M /d.sub.D =              ______________________________________                                         0.56                                                                      

                  TABLE 19                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0 FNo..sub.M = 3.0 2ω.sub.M =             20° f.sub.S = 24.295 mm                                                 β.sub.S = -0.468 eff. FNo..sub.S = 3.0 λ = 632.8 nm                radius of     axial      refractive                                            curvature     distance   index                                                 ______________________________________                                         r.sub.1 (stop)                                                                                   d.sub.1                                                                              18.246                                                 r.sub.2 -36.446                                                                                  d.sub.2                                                                              2.248  n.sub.1 1.51508                                 r.sub.3 46.000                                                                                   d.sub.3                                                                              9.267                                                  r.sub.4 102.587                                                                                  d.sub.4                                                                              4.637  n.sub.2 1.74969                                 r.sub.5 -65.479                                                                                  d.sub.5                                                                              14.111                                                 r.sub.6 63.493                                                                                   d.sub.6                                                                              10.032 n.sub.3 1.74969                                 r.sub.7 366.156                                                                                  d.sub.7                                                                              19.044                                                 r.sub.8M                                                                               117.938                                                                r.sub.8S                                                                               51.204                                                                                   d.sub.8                                                                              4.905  n.sub.4 1.74969                                 r.sub.9 -205.162                                                                                 d.sub.9                                                                              2.153                                                  r.sub.10                                                                               50.710                                                                                   d.sub.10                                                                             7.501  n.sub.5 1.74969                                 r.sub.11                                                                               -915.642                                                                                 d.sub.11                                                                             2.064                                                  r.sub.12                                                                               -55.476                                                                                  d.sub.12                                                                             2.622  n.sub.6 1.74969                                 r.sub.13                                                                               29.374                                                                                   d.sub.13                                                                             4.474                                                  r.sub.14                                                                               59.383                                                                                   d.sub.14                                                                             3.291  n.sub.7 1.74969                                 r.sub.15                                                                               510.189                                                                                  d.sub.15                                                                             2.999                                                  r.sub.16M                                                                              ∞                                                                r.sub.16S                                                                              11.545                                                                                   d.sub.16                                                                             3.568  n.sub.8 1.80094                                 r.sub.17M                                                                              ∞                                                                r.sub.17S                                                                              -434.346                                                                                 d.sub.17                                                                             0.500                                                  r.sub.18M                                                                              ∞                                                                r.sub.18S                                                                              -46.420                                                                                  d.sub.18                                                                             3.000  n.sub.9 1.80094                                 r.sub.19M                                                                              ∞                                                                r.sub.19S                                                                              47.690                                                                                   Σd                                                                             114.662                                                                               (s' = 10.827)                                   f.sub.M /r.sub.A = f.sub.M /r.sub.3 = 0.98, f.sub.M /r.sub.B = f.sub.M         /r.sub.6 = 0.71,                                                               -f.sub.M /r.sub.C = -f.sub.M /r.sub.12 = 0.81, f.sub.M /d.sub.D =              ______________________________________                                         0.47                                                                      

                  TABLE 20                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0 FNo..sub.M = 3.0 2ω.sub.M =             20° f.sub.S = 24.732 mm                                                 β.sub.S = -0.603 eff. FNo..sub.S = 3.0 λ = 632.8 nm                radius of     axial      refractive                                            curvature     distance   index                                                 ______________________________________                                         r.sub.1 (stop)                                                                                   d.sub.1                                                                              19.584                                                 r.sub.2 -26.576                                                                                  d.sub.2                                                                              2.200  n.sub.1 1.51508                                 r.sub.3 81.049                                                                                   d.sub.3                                                                              7.887                                                  r.sub.4 -53.686                                                                                  d.sub.4                                                                              3.603  n.sub.2 1.51508                                 r.sub.5 -39.508                                                                                  d.sub.5                                                                              0.210                                                  r.sub.6 261.764                                                                                  d.sub.6                                                                              4.971  n.sub.3 1.74969                                 r.sub.7 -53.080                                                                                  d.sub.7                                                                              12.149                                                 r.sub.8M                                                                               56.597                                                                 r.sub.8S                                                                               108.403                                                                                  d.sub.8                                                                              7.108  n.sub.4 1.69584                                 r.sub.9M                                                                               -901.575                                                               r.sub.9S                                                                               -54.694                                                                                  d.sub.9                                                                              14.746                                                 r.sub.10                                                                               64.128                                                                                   d.sub.10                                                                             6.579  n.sub.5 1.80094                                 r.sub.11                                                                               -181.756                                                                                 d.sub.11                                                                             5.399                                                  r.sub.12                                                                               -71.968                                                                                  d.sub.12                                                                             2.180  n.sub.6 1.80094                                 r.sub.13                                                                               31.121                                                                                   d.sub. 13                                                                            2.317                                                  r.sub.14                                                                               110.960                                                                                  d.sub.14                                                                             3.410  n.sub.7 1.80094                                 r.sub.15                                                                               85.678                                                                                   d.sub.15                                                                             5.007                                                  r.sub.16M                                                                              ∞                                                                r.sub.16S                                                                              14.275                                                                                   d.sub.16                                                                             3.068  n.sub.8 1.80094                                 r.sub.17M                                                                              ∞                                                                r.sub.17S                                                                              -902.528                                                                                 d.sub.17                                                                             0.500                                                  r.sub.18M                                                                              ∞                                                                r.sub.18S                                                                              -63.714                                                                                  d.sub.18                                                                             3.000  n.sub.9 1.80094                                 r.sub.19M                                                                              ∞                                                                r.sub.19S                                                                              60.562                                                                                   Σd                                                                             103.918                                                                               (s' = 16.105)                                   f.sub.M /r.sub.A = f.sub.M /r.sub.3 = 0.56, f.sub.M /r.sub.B = f.sub.M         /r.sub.8M = 0.80,                                                              -f.sub.M /r.sub.C = -f.sub.M /r.sub.12 = 0.63, f.sub.M /d.sub.D =              ______________________________________                                         0.53                                                                      

                  TABLE 21                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0  FNo..sub.M = 3.0 2ω.sub.M =            20° f.sub.S = 23.374 mm                                                 β.sub.S = -0.703 eff. FNo..sub.S = 3.0 λ = 632.8 nm                radius of     axial      refractive                                            curvature     distance   index                                                 ______________________________________                                         r.sub.1 (stop)                                                                 r.sub.2 -29.886                                                                                  d.sub.2                                                                              2.250  n.sub.1 1.74969                                 r.sub.3 70.459                                                                                   d.sub.3                                                                              8.477                                                  r.sub.4 604.003                                                                                  d.sub.4                                                                              5.097  n.sub.2 1.74969                                 r.sub.5 -43.260                                                                                  d.sub.5                                                                              3.754                                                  r.sub.6M                                                                               56.527                                                                 r.sub.6S                                                                               49.459                                                                                   d.sub.6                                                                              9.950  n.sub.3 1.80094                                 r.sub.7 -117.323                                                                                 d.sub.7                                                                              18.182                                                 r.sub.8M                                                                               62.399                                                                 r.sub.8S                                                                               67.203                                                                                   d.sub.8                                                                              5.320  n.sub.4 1.80094                                 r.sub.9 -94.875                                                                                  d.sub.9                                                                              1.350                                                  r.sub.10                                                                               -48.774                                                                                  d.sub.9                                                                              10.101 n.sub.5 1.80094                                 r.sub.11                                                                               30.767                                                                                   d.sub.11                                                                             1.782                                                  r.sub.12                                                                               68.762                                                                                   d.sub. 12                                                                            3.261  n.sub.6 1.80094                                 r.sub.13                                                                               -108.436                                                                                 d.sub.13                                                                             2.000                                                  r.sub.14M                                                                              ∞                                                                r.sub.14S                                                                              15.109                                                                                   d.sub.14                                                                             4.000  n.sub.7 1.80094                                 r.sub.15M                                                                              ∞                                                                r.sub.15S                                                                              202.535                                                                                  d.sub.15                                                                             0.500                                                  r.sub.16M                                                                              ∞                                                                r.sub.16S                                                                              -57.768                                                                                  d.sub.16                                                                             3.000  n.sub.8 1.80094                                 r.sub.17M                                                                              ∞                                                                r.sub.17S                                                                              102.417                                                                                  Σd                                                                             99.379 (s' = 23.635)                                   f.sub.M /r.sub.A = f.sub.M /r.sub.3 = 0.64, f.sub.M /r.sub.B = f.sub.M         /r.sub.6M = 0.80,                                                              -f.sub.M /r.sub.C = -f.sub.M /r.sub.10 = 0.92, f.sub.M /d.sub.D =              ______________________________________                                         0.57                                                                      

                  TABLE 22                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0 FNo..sub.M = 3.0 2ω.sub.M =             20° f.sub.S = 24.286 mm                                                 β.sub.S = -0.598 eff.FNo..sub.S = 3.0 λ = 632.8 nm                 radius of     axial       refractive                                           curvature     distance    index                                                ______________________________________                                         r.sub.1                                                                             (stop)       d.sub.1                                                                              19.036                                                 r.sub.2                                                                             -24.665      d.sub.2                                                                              2.200   n.sub.1                                                                             1.51508                                   r.sub.3                                                                             80.119       d.sub.3                                                                              8.100                                                  r.sub.4                                                                             -53.813      d.sub.4                                                                              3.800   n.sub.2                                                                             1.51508                                   r.sub.5                                                                             -39.341      d.sub.5                                                                              0.300                                                  r.sub.6                                                                             274.477      d.sub.6                                                                              5.000   n.sub.3                                                                             1.74969                                   r.sub.7                                                                             -53.063      d.sub.7                                                                              11.300                                                 r.sub.8                                                                             57.405       d.sub.8                                                                              6.200   n.sub.4                                                                             1.74969                                   r.sub.9                                                                             -1009.601    d.sub.9                                                                              3.700                                                  r.sub.10M                                                                           ∞                                                                   r.sub.10S                                                                           51.108       d.sub.10                                                                             4.000   n.sub.5                                                                             1.51508                                   r.sub.11                                                                            ∞      d.sub.11                                                                             2.000                                                  r.sub.12M                                                                           ∞                                                                   r.sub.12S                                                                           -73.201      d.sub.12                                                                             4.000   n.sub.6                                                                             1.51508                                   r.sub.13                                                                            ∞      d.sub.13                                                                             3.700                                                  r.sub.14                                                                            79.483       d.sub.14                                                                             6.000   n.sub.7                                                                             1.74969                                   r.sub.15                                                                            -191.221     d.sub.15                                                                             5.840                                                  r.sub.16                                                                            -70.410      d.sub.16                                                                             2.100   n.sub.8                                                                             1.74969                                   r.sub.17                                                                            31.151       d.sub.17                                                                             2.300                                                  r.sub.18                                                                            107.494      d.sub.18                                                                             3.200   n.sub.9                                                                             1.74969                                   r.sub.19                                                                            -69.424      d.sub.19                                                                             3.000                                                  r.sub.20M                                                                           ∞                                                                   r.sub.20S                                                                           28.074       d.sub.20                                                                             3.000   n.sub.10                                                                            1.80094                                   r.sub.21M                                                                           ∞                                                                   r.sub.21S                                                                           106.862      d.sub.21                                                                             1.000                                                  r.sub.22M                                                                           ∞                                                                   r.sub.22S                                                                           13.797       d.sub.22                                                                             3.000   n.sub.11                                                                            1.80094                                   r.sub.23M                                                                           ∞                                                                   r.sub.23S                                                                           16.424       Σd                                                                             102.776      (s' = 18.387)                             f.sub.M /r.sub.A = f.sub.M /r.sub.3 = 0.56, f.sub.M /r.sub.B = f.sub.M         /r.sub.B = 0.78,                                                               -f.sub.M /r.sub.C = -f.sub.M /r.sub.16 = 0.64, f.sub.M /d.sub.D =              ______________________________________                                         0.54                                                                      

                  TABLE 23                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0 FNo..sub.M = 3.0 2ω.sub.M =             20° f.sub.S = 24.993 mm                                                 β.sub.S = -0.698 eff.FNo..sub.S = 3.0 λ = 632.8 nm                 radius of      axial       refractive                                          curvature      distance    index                                               ______________________________________                                         r.sub.1                                                                               (stop)      d.sub.1                                                                              18.378                                                r.sub.2                                                                               -26.328     d.sub.2                                                                              2.250   n.sub.1                                                                             1.51508                                  r.sub.3                                                                               73.344      d.sub.3                                                                              5.238                                                 r.sub.4                                                                               -50.692     d.sub.4                                                                              6.667   n.sub.2                                                                             1.51508                                  r.sub.5                                                                               -35.558     d.sub.5                                                                              0.011                                                 r.sub.6                                                                               104.051     d.sub.6                                                                              4.872   n.sub.3                                                                             1.51508                                  r.sub.7                                                                               -48.724     d.sub.7                                                                              5.000                                                 r.sub.8M                                                                              ∞                                                                 r.sub.8S                                                                              -37.970     d.sub.8                                                                              3.000   n.sub.4                                                                             1.74969                                  r.sub.9M                                                                              ∞                                                                 r.sub.9S                                                                              -26.699     d.sub.9                                                                              2.280                                                 r.sub.10                                                                              51.521      d.sub.10                                                                             6.234   n.sub.5                                                                             1.61052                                  r.sub.11                                                                              -263.698    d.sub.11                                                                             7.500                                                 r.sub.12M                                                                             ∞                                                                 r.sub.12S                                                                             -24.676     d.sub.12                                                                             3.000   n.sub.6                                                                             1.80094                                  r.sub.13M                                                                             ∞                                                                 r.sub.13S                                                                             -30.747     d.sub.13                                                                             6.040                                                 r.sub.14                                                                              60.918      d.sub.14                                                                             5.973   n.sub.7                                                                             1.74969                                  r.sub.15                                                                              -315.687    d.sub.15                                                                             2.838                                                 r.sub.16                                                                              -66.743     d.sub.16                                                                             2.149   n.sub.8                                                                             1.51508                                  r.sub.17                                                                              25.557      d.sub.17                                                                             4.330                                                 r.sub.18                                                                              206.147     d.sub.18                                                                             2.322   n.sub.9                                                                             1.74969                                  r.sub.19                                                                              -93.233     d.sub.19                                                                             3.000                                                 r.sub.20M                                                                             ∞                                                                 r.sub.20S                                                                             17.139      d.sub.20                                                                             4.005   n.sub.10                                                                            1.80094                                  r.sub.21M                                                                             ∞                                                                 r.sub.21S                                                                             46.857      Σd                                                                             95.087       (s' = 23.184)                            f.sub.M /r.sub.A = f.sub.M /r.sub.3 = 0.61, f.sub.M /r.sub.B = f.sub.M         /r.sub.10 = 0.87,                                                              -f.sub.M /r.sub.C = -f.sub.M /r.sub.16 = 0.67, .sub.M /d.sub.D                 ______________________________________                                         = 0.59                                                                    

                  TABLE 24                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0 FNo..sub.M = 3.0 2ω.sub.M =             20° f.sub.S = 24.097 mm                                                 β.sub.S = -0.547 eff.FNo..sub.S = 3.0 λ = 632.8 nm                 radius of      axial       refractive                                          curvature      distance    index                                               ______________________________________                                         r.sub.1                                                                               (stop)      d.sub.1                                                                              20.009                                                r.sub.2                                                                               -26.702     d.sub.2                                                                              2.200   n.sub.1                                                                             1.51508                                  r.sub.3                                                                               80.897      d.sub.3                                                                              8.200                                                 r.sub.4                                                                               -53.647     d.sub.4                                                                              3.700   n.sub.2                                                                             1.51508                                  r.sub.5                                                                               -39.484     d.sub.5                                                                              0.300                                                 r.sub.6                                                                               272.428     d.sub.6                                                                              5.600   n.sub.3                                                                             1.74969                                  r.sub.7                                                                               53.135      d.sub.7                                                                              11.300                                                r.sub.8                                                                               57.527      d.sub.8                                                                              6.000   n.sub.4                                                                             1.74969                                  r.sub.9                                                                               -985.416    d.sub.9                                                                              7.500                                                 r.sub.10M                                                                             ∞                                                                 r.sub.10S                                                                             125.000     d.sub.10                                                                             4.000   n.sub.5                                                                             1.51508                                  r.sub.11                                                                              ∞     d.sub.11                                                                             4.500                                                 r.sub.12                                                                              67.334      d.sub.12                                                                             6.000   n.sub.6                                                                             1.74969                                  r.sub.13                                                                              -234.412    d.sub.13                                                                             5.800                                                 r.sub.14                                                                              -74.006     d.sub.14                                                                             2.100   n.sub.7                                                                             1.74969                                  r.sub.15                                                                              30.225      d.sub.15                                                                             2.300                                                 r.sub.16                                                                              125.790     d.sub.16                                                                             3.800   n.sub.8                                                                             1.74969                                  r.sub.17                                                                              -74.812     d.sub.17                                                                             2.766                                                 r.sub.18M                                                                             ∞                                                                 r.sub.18S                                                                             20.500      d.sub.18                                                                             4.000   n.sub.9                                                                             1.80094                                  r.sub.19M                                                                             ∞                                                                 r.sub.19S                                                                             -50.000     d.sub.19                                                                             0.531                                                 r.sub.20M                                                                             ∞                                                                 r.sub.20S                                                                             -25.500     d.sub.20                                                                             2.850   n.sub.10                                                                            1.80094                                  r.sub.21M                                                                             ∞                                                                 r.sub.21S                                                                             -50.000     Σd                                                                             103.456      (s' = 17.858)                            f.sub.M /r.sub.A = f.sub.M /r.sub.3 = 0.56, f.sub.M /r.sub.B = f.sub.M         /r.sub.8 = 0.78,                                                               -f.sub.M /r.sub.C = -f.sub.M /r.sub.14 = 0.61, f.sub.M /d.sub.D =              ______________________________________                                         0.54                                                                      

                  TABLE 25                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0 FNo..sub.M = 3.0 2ω.sub.M =             20° f.sub.S = 23.626 mm                                                 β.sub.S = -0.579 eff.FNo..sub.S = 3.0 λ = 632.8 nm                 radius of     axial       refractive                                           curvature     distance    index                                                ______________________________________                                         r.sub.1                                                                             (stop)       d.sub.1                                                                              19.491                                                 r.sub.2                                                                             -26.626      d.sub.2                                                                              2.100   n.sub.1                                                                             1.51508                                   r.sub.3                                                                             80.291       d.sub.3                                                                              8.100                                                  r.sub.4                                                                             -53.762      d.sub.4                                                                              3.800   n.sub.2                                                                             1.51508                                   r.sub.5                                                                             -39.404      d.sub.5                                                                              0.305                                                  r.sub.6                                                                             274.080      d.sub.6                                                                              5.007   n.sub.3                                                                             1.74969                                   r.sub.7                                                                             -53.105      d.sub.7                                                                              10.302                                                 r.sub.8                                                                             57.356       d.sub.8                                                                              6.198   n.sub.4                                                                             1.74969                                   r.sub.9                                                                             -1001.091    d.sub.9                                                                              7.500                                                  r.sub.10M                                                                           ∞                                                                   r.sub.10S                                                                           127.517      d.sub.10                                                                             4.000   n.sub.5                                                                             1.51508                                   r.sub.11                                                                            ∞      d.sub.11                                                                             4.500                                                  r.sub.12                                                                            75.141       d.sub.12                                                                             5.978   n.sub.6                                                                             1.74969                                   r.sub.13                                                                            -187.074     d.sub.13                                                                             5.979                                                  r.sub.14                                                                            -68.515      d.sub.14                                                                             2.105   n.sub.7                                                                             1.74969                                   r.sub.15                                                                            31.055       d.sub.15                                                                             2.351                                                  r.sub.16                                                                            106.965      d.sub.16                                                                             3.800   n.sub.8                                                                             1.74969                                   r.sub.17                                                                            -74.073      d.sub.17                                                                             2.500                                                  r.sub.18M                                                                           ∞                                                                   r.sub.18S                                                                           16.975       d.sub.18                                                                             4.000   n.sub.9                                                                             1.80094                                   r.sub.19M                                                                           ∞                                                                   r.sub.19S                                                                           -105.637     d.sub.19                                                                             0.800                                                  r.sub.20M                                                                           ∞                                                                   r.sub.20S                                                                           -39.334      d.sub.20                                                                             3.000   n.sub.10                                                                            1.80094                                   r.sub.21                                                                            ∞      Σd                                                                             102.816      (s' = 17.766)                             f.sub.M /r.sub.A = f.sub.M /r.sub.3 = 0.56, .sub.M /r.sub.B = f.sub.M          /r.sub.8 = 0.78,                                                               -f.sub.M /r.sub.C = -f.sub.M /r.sub.14 = 0.66, f.sub.M /d.sub.D =              ______________________________________                                         0.54                                                                      

                  TABLE 26                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0 FNo..sub.M = 3.0 2ω.sub.M =             20° f.sub.S = 24.828 mm                                                 β.sub.S = -0.490 eff.FNo..sub.S = 3.0 λ = 632.8 nm                 radius of      axial       refractive                                          curvature      distance    index                                               ______________________________________                                         r.sub.1                                                                               (stop)      d.sub.1                                                                              21.602                                                r.sub.2                                                                               -24.200     d.sub.2                                                                              2.200   n.sub.1                                                                             1.51508                                  r.sub.3                                                                               93.855      d.sub.3                                                                              8.100                                                 r.sub.4                                                                               -105.673    d.sub.4                                                                              4.988   n.sub.2                                                                             1.51508                                  r.sub.5                                                                               -46.500     d.sub.5                                                                              0.361                                                 r.sub.6                                                                               326.525     d.sub.6                                                                              5.157   n.sub.3                                                                             1.74969                                  r.sub.7                                                                               -46.263     d.sub.7                                                                              10.281                                                r.sub.8                                                                               56.259      d.sub.8                                                                              6.547   n.sub.4                                                                             1.74969                                  r.sub.9                                                                               174.901     d.sub.9                                                                              11.448                                                r.sub.10M                                                                             ∞                                                                 r.sub.10S                                                                             83.243      d.sub.10                                                                             4.000   n.sub.5                                                                             1.51508                                  r.sub.11                                                                              ∞     d.sub.11                                                                             2.000                                                 r.sub.12                                                                              53.147      d.sub.12                                                                             6.000   n.sub.6                                                                             1.74969                                  r.sub.13                                                                              147.022     d.sub.13                                                                             6.571                                                 r.sub.14                                                                              ∞     d.sub.14                                                                             3.150   n.sub.7                                                                             1.74969                                  r.sub. 15                                                                             26.058      d.sub.15                                                                             1.800                                                 r.sub.16                                                                              51.722      d.sub.16                                                                             3.200   n.sub.8                                                                             1.74969                                  r.sub.17                                                                              -280.861    d.sub.17                                                                             2.766                                                 r.sub.18M                                                                             ∞                                                                 r.sub.18S                                                                             18.234      d.sub.18                                                                             4.000   n.sub.9                                                                             1.80094                                  r.sub.19M                                                                             ∞                                                                 r.sub.19S                                                                             -56.012     d.sub.19                                                                             0.531                                                 r.sub.20M                                                                             ∞                                                                 r.sub.20S                                                                             -22.023     d.sub.20                                                                             2.850   n.sub.10                                                                            1.80094                                  r.sub.21M                                                                             ∞                                                                 r.sub.21S                                                                             -34.654     Σd                                                                             107.552      (s' = 14.659)                            f.sub.M /r.sub.A = f.sub.M /r.sub.3 = 0.48, f.sub.M /r.sub.B = f.sub.M         /r.sub.8 = 0.80,                                                               -f.sub.M /r.sub.C = -f.sub.M /r.sub.14 = 0, f.sub.M /d.sub.D                   ______________________________________                                         = 0.52                                                                    

                  TABLE 27                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0 FNo..sub.M = 3.0 2ω.sub.M =             20° f.sub.S = 23.989 mm                                                 β.sub.S = -0.590 eff.FNo..sub.S = 3.0 λ = 632.8 nm                 radius of      axial       refractive                                          curvature      distance    index                                               ______________________________________                                         r.sub.1                                                                               (stop)      d.sub.1                                                                              17.104                                                r.sub.2                                                                               -25.586     d.sub.2                                                                              2.240   n.sub.1                                                                             1.51508                                  r.sub.3                                                                               65.820      d.sub.3                                                                              6.200                                                 r.sub.4                                                                               -48.018     d.sub.4                                                                              8.742   n.sub.2                                                                             1.51508                                  r.sub.5                                                                               -35.283     d.sub.5                                                                              0.011                                                 r.sub.6                                                                               125.688     d.sub.6                                                                              6.000   n.sub.3                                                                             1.51508                                  r.sub.7                                                                               -47.370     d.sub.7                                                                              9.074                                                 r.sub.8                                                                               47.992      d.sub.8                                                                              6.234   n.sub.4                                                                             1.74969                                  r.sub.9                                                                               -347.814    d.sub.9                                                                              11.032                                                r.sub.10M                                                                             ∞                                                                 r.sub.10S                                                                             106.886     d.sub.10                                                                             4.000   n.sub.5                                                                             1.51508                                  r.sub.11                                                                              ∞     d.sub.11                                                                             3.000                                                 r.sub.12                                                                              50.490      d.sub.12                                                                             5.973   n.sub.6                                                                             1.51508                                  r.sub.13                                                                              -270.366    d.sub.13                                                                             1.350                                                 r.sub.14                                                                              -62.678     d.sub.14                                                                             2.149   n.sub.7                                                                             1.80094                                  r.sub. 15                                                                             30.587      d.sub.15                                                                             5.974                                                 r.sub.16                                                                              178.557     d.sub.16                                                                             2.520   n.sub.8                                                                             1.74969                                  r.sub.17                                                                              -57.946     d.sub.17                                                                             2.766                                                 r.sub.18M                                                                             ∞                                                                 r.sub.18S                                                                             21.693      d.sub.18                                                                             4.000   n.sub.9                                                                             1.80094                                  r.sub.19M                                                                             ∞                                                                 r.sub.19S                                                                             -48.315     d.sub.19                                                                             0.531                                                 r.sub.20M                                                                             ∞                                                                 r.sub.20S                                                                             -28.375     d.sub.20                                                                             2.850   n.sub.10                                                                            1.80094                                  r.sub.21M                                                                             ∞                                                                 r.sub.21S                                                                             -73.462     Σd                                                                             101.750      (s' = 19.382)                            f.sub.M /r.sub.A = f.sub.M /r.sub.3 = 0.68, f.sub.M /r.sub.B = f.sub.M         /r.sub.8 = 0.94,                                                               -f.sub.M /r.sub.C = -f.sub.M /r.sub.14 = 0.72, f.sub.M /d.sub.D =              ______________________________________                                         0.53                                                                      

                  TABLE 28                                                         ______________________________________                                         f.sub.M = 45 mm β.sub.M = 0 FNo..sub.M = 3.0 2ω.sub.M =             20° f.sub.S = 31.421 mm                                                 β.sub.S = -0.445 eff.FNo..sub.S = 3.0 λ = 632.8 nm                 radius of      axial       refractive                                          curvature      distance    index                                               ______________________________________                                         r.sub.1                                                                               (stop)      d.sub.1                                                                              12.243                                                r.sub.2                                                                               -27.049     d.sub.2                                                                              2.251   n.sub.1                                                                             1.51508                                  r.sub.3                                                                               51.085      d.sub.3                                                                              10.358                                                r.sub.4                                                                               219.397     d.sub.4                                                                              5.331   n.sub.2                                                                             1.51508                                  r.sub.5                                                                               -34.191     d.sub.5                                                                              9.044                                                 r.sub.6                                                                               65.589      d.sub.6                                                                              6.799   n.sub.3                                                                             1.51508                                  r.sub.7                                                                               -93.098     d.sub.7                                                                              13.298                                                r.sub.8M                                                                              ∞                                                                 r.sub.8S                                                                              85.573      d.sub.8                                                                              4.000   n.sub.4                                                                             1.51508                                  r.sub.9                                                                               ∞     d.sub.9                                                                              4.500                                                 r.sub.10                                                                              45.100      d.sub.10                                                                             10.800  n.sub.5                                                                             1.80094                                  r.sub.11                                                                              -171.957    d.sub.11                                                                             4.287                                                 r.sub.12                                                                              -69.243     d.sub.12                                                                             12.314  n.sub.6                                                                             1.80094                                  r.sub.13                                                                              26.245      d.sub.13                                                                             6.739                                                 r.sub.14                                                                              68.183      d.sub.14                                                                             2.700   n.sub.7                                                                             1.80094                                  r.sub.15                                                                              - 107.008   d.sub.15                                                                             5.000                                                 r.sub.16M                                                                             ∞                                                                 r.sub.16S                                                                             11.658      d.sub.16                                                                             4.000   n.sub.8                                                                             1.80094                                  r.sub.17M                                                                             ∞                                                                 r.sub.17S                                                                             -52.790     d.sub.17                                                                             0.531                                                 r.sub.18M                                                                             ∞                                                                 r.sub.18S                                                                             -22.862     d.sub.18                                                                             2.850   n.sub.9                                                                             1.80094                                  r.sub.19M                                                                             ∞                                                                 r.sub.19S                                                                             -152.061    Σd                                                                             117.054      (s' = 10.153)                            f.sub.M /r.sub.A = f.sub.M /r.sub.3 = 0.88, f.sub.M /r.sub.B = f.sub.M         /r.sub.6 = 0.69,                                                               -f.sub.M /r.sub.C = -f.sub.M /r.sub.12 = 0.65, f.sub.M /d.sub.D =              ______________________________________                                         0.43                                                                       

What is claimed is:
 1. A telecentric fθ lens system for use in a laser COM comprising, from the object to image side:a first lens unit including a negative lens component; a second lens unit consisting of a positive lens component; a third lens unit including a positive lens component; and a fourth lens unit including three lens components, of which two lens components are a negative and a positive lens component aligned in order from the object side and the final lens component from the object side is positive, wherein said lens components are respectively spaced from each other on an optical axis.
 2. A telecentric fθ lens system as claimed in claim 1 wherein the fourth lens unit includes a positive lens component, a negative lens component and a positive lens component in order from the object field side.
 3. A telecentric fθ lens system as claimed in claim 1 further fulfilling the following conditions:0≦f/r_(A) <1 0.6<f/r_(B) <1 0≦-f/r_(C) <1 0.4<f/d_(D) <0.7wherein f is a total focal length of the lens system, r_(A) is a radius of curvature of the image field side surface of the negative lens component in the first lens unit, r_(B) is a radius of curvature of the object field side surface of the positive lens component in the third lens unit, r_(C) is a radius of curvature of the object field side surface of the negative lens component in the fourth lens unit and d_(D) is an axial distance of the whole lens system.
 4. A telecentric fθ lens system as claimed in claim 1 further comprising a fifth lens unit of an anamorphic characteristic in which a refractive power thereof in the sagittal direction is larger than a refractive power in the meridional direction.
 5. A telecentric fθ lens system as claimed in claim 1, wherein the fourth lens unit includes two positive lens components, a negative lens component and a positive lens component, in order from the object field side.
 6. A telecentric fθ lens system for use in a laser COM comprising, from the object to the image side:a first lens unit including a negative lens component; a second lens unit consisting of a positive lens component; a third lens unit including a positive lens component; a fourth lens unit including three lens components; and a fifth lens unit of an anamorphic characteristic in which a refractive power thereof in the sagittal direction is larger than a refractive power in the meridional direction; wherein one lens surface of the third lens unit is an anamorphic surface.
 7. A telecentric fθ lens system as claimed in claim 6 wherein the fourth lens unit includes a positive lens component, a negative lens component and a positive lens component in order from the object field side.
 8. A telecentric fθ lens system as claimed in claim 6 further fulfilling the following conditions:0≦f_(M) /r_(A) <1 0.6<f_(M) /r_(B) <1 0≦-f_(M) /r_(C) <1 0.4<f_(M) /d_(D) <0.7wherein f_(M) is a total focal length of the lens system in the meridional direction, r_(A) is a radius of curvature of the image field side surface of the negative lens in the first lens component unit, r_(B) is a radius of curvature of the object field side surface of the positive lens component in the third lens unit, r_(C) is a radius of curvature of the object field side surface of the negative lens component in the fourth lens unit and d_(D) is an axial distance of the whole lens system.
 9. A telecentric fθ lens system as claimed in claim 6, further fulfilling the following conditions:0≦f_(M) /r_(A) <1 0.6<f_(M) /r_(B) <1 0≦-f_(M) /r_(C) <1 0.4<f_(M) /d_(D) <0.6wherein f_(M) is a total focal length of the lens system in the meridional direction, r_(A) is a radius of curvature of the image field side surface of the negative lens component in the first lens unit, r_(B) is a radius of curvature of the object field side surface of the positive lens component in the third lens unit, r_(C) is a radius of curvature of the object field side surface of the negative lens component in the fourth lens unit, and d_(D) is an axial distance of the whole lens system.
 10. A telecentric fθ lens system as claimed in claim 6, further fulfilling the following conditions:f_(S) <f_(M) 0.4<-β_(S) <0.8wherein: f_(S) =a total focal length of the lens system in the sagittal direction, f_(M) =a total focal length of the lens system in the meridional direction, β_(S) =a magnification in the sagittal direction.
 11. A telecentric fθ lens system for use in a laser COM comprising, from the object to the image side:a first lens unit including a negative lens component; a second lens unit consisting of two positive lens components; a third lens unit including a positive lens component, and a fourth lens unit including three lens components, of which two lens components are a negative and a positive lens component aligned in order from the object side and the final lens component from the object side is positive, wherein said lens components are respectively spaced from each other on an optical axis.
 12. A telecentric fθ lens system as claimed in claim 11, wherein the fourth lens unit includes a positive lens component, a negative lens component and a positive lens component in order from the object field side.
 13. A telecentric fθ lens system as claimed in claim 11, wherein the fourth lens unit includes two positive lens components, a negative lens component and a positive lens component in order from the object field side.
 14. A telecentric fθ lens system as claimed in claim 11, further fulfilling the following conditions:0≦f/r_(A) <1 0.6<f/r_(B) <1 0≦-f/r_(C) <1 0.4<f/d_(D) <0.7 wherein f is a total focal length of the lens system, r_(A) is a radius of curvature of the image field side surface of the negative lens component in the first lens unit, r_(B) is a radius of curvature of the object field side surface of the positive lens component in the third lens unit, r_(C) is a radius of curvature of the object field side surface of the negative lens component in the fourth lens unit, and d_(D) is an axial distance of the whole lens system.
 15. A telecentric fθ lens system as claimed in claim 11, further comprising a fifth lens unit of an anamorphic characteristic in which a refractive power thereof in the sagittal direction is larger than a refractive power in the meridional direction.
 16. A telecentric fθ lens system for use in a laser COM comprising, from the object to the image side:a first lens unit including a negative lens component; a second lens unit consisting of a positive lens component; a third lens unit including a positive lens component; a fourth lens unit including three lens components, and a fifth lens unit of an anamorphic characteristic in which a refractive power thereof in the sagittal direction is larger than a refractive power in the meridional direction, wherein one lens surface of the fourth lens unit is an anamorphic surface.
 17. A telecentric fθ lens system as claimed in claim 16, wherein the fourth lens unit includes a positive lens component, a negative lens component and a positive lens component in order from the object field side.
 18. A telecentric fθ lens system as claimed in claim 16, wherein the fourth lens unit includes two positive lens components, a negative lens component and a positive lens component in order from the object field side.
 19. A telecentric fθ lens system as claimed in claim 16, further fulfilling the following conditions:0≦f_(M) /r_(A) <1 0.6<f_(M) /r_(B) <1 0≦-f_(M) /r_(C) <1 0.4<f_(M) /d_(D) <0.7 wherein f_(M) is a total focal length of the lens system in the meridional direction, r_(A) is a radius of curvature of the image field side surface of the negative lens component in the first lens unit, r_(B) is a radius of curvature of the object field side surface of the positive lens component in the third lens unit, r_(C) is a radius of curvature of the object field side surface of the negative lens component in the fourth lens unit, and d_(D) is an axial distance of the whole lens system.
 20. A telecentric fθ lens system as claimed in claim 16, further fulfilling the following conditions:0≦f_(M) /r_(A) <1 0.6<f_(M) /r_(B) <1 0≦-f_(M) /r_(C) <1 0.4<f_(M) /d_(D) <0.6 wherein f_(M) is a total focal length of the lens system in the meridional direction, r_(A) is a radius of curvature of the image field side surface of the negative lens component in the first lens unit, r_(B) is a radius of curvature of the object field side surface of the positive lens component in the third lens unit, r_(C) is a radius of curvature of the object field side surface of the negative lens component in the fourth lens unit, and d_(D) is an axial distance of the whole lens system.
 21. A telecentric fθ lens system as claimed in claim 16, further fulfilling the following conditions:f_(s) <f_(M) 0.4<-β_(s) <0.8wherein: f_(s) =a total focal length of the lens system in the sagittal direction, f_(M) =a total focal length of the lens system in the meridional direction, and β_(s) =a magnification in the sagittal direction.
 22. A telecentric fθ lens system for use in a laser COM comprising, from the object to the image side:a first lens unit including a negative lens component; a second lens unit consisting of two positive lens components; a third lens unit including a positive lens component; a fourth lens unit including three lens components, and a fifth lens unit of an anamorphic characteristic in which a refractive power thereof in the sagittal direction is larger than a refractive power in the meridional direction, wherein one lens surface of the third lens unit is an anamorphic surface.
 23. A telecentric fθ lens system as claimed in claim 22, wherein the fourth lens unit includes a positive lens component, a negative lens component and a positive lens component in order from the object field side.
 24. A telecentric fθ lens system as claimed in claim 22, wherein the fourth lens unit includes two positive lens components, a negative lens component and a positive lens component in order from the object field side.
 25. A telecentric fθ lens system as claimed in claim 22, further fulfilling the following conditions:0≦f_(M) /r_(A) <1 0.6<f_(M) /r_(B) <1 0≦-f_(M) /r_(C) <1 0.4<f_(M) /d_(D) <0.7 wherein f_(M) is a total focal length of the lens system in the meridional direction, r_(A) is a radius of curvature of the image field side surface of the negative lens component in the first lens unit, r_(B) is a radius of curvature of the object field side surface of the positive lens component in the third lens unit, r_(C) is a radius of curvature of the object field side surface of the negative lens component in the fourth lens unit, and d_(D) is an axial distance of the whole lens system.
 26. A telecentric fθ lens system as claimed in claim 22, further fulfilling the following conditions:0≦f_(M) /r_(A) <1 0.6<f_(M) /r_(B) <1 0≦-f_(M) /r_(C) <1 0.4<f_(M) /d_(D) <0.6 wherein f_(M) is a total focal length of the lens system in the meridional direction, r_(A) is a radius of curvature of the image field side surface of the negative lens component in the first lens unit, r_(B) is a radius of curvature of the object field side surface of the positive lens component in the third lens unit, r_(C) is a radius of curvature of the object field side surface of the negative lens component in the fourth lens unit, and d_(D) is an axial distance of the whole lens system.
 27. A telecentric fθ lens system as claimed in claim 22, further fulfilling the following conditions:f_(s) <f_(M) 0.4<-β_(s) <0.8wherein: f_(s) =a total focal length of the lens system in the sagittal direction, f_(M) =a total focal length of the lens system in the meridional direction, and β_(s) =a magnification in the sagittal direction.
 28. A telecentric fθ lens system for use in a laser COM comprising, from the object to the image side:a first lens unit including a negative lens component; a second lens unit consisting of two positive lens components; a third lens unit including a positive lens component; a fourth lens unit including three lens components, and a fifth lens unit of an anamorphic characteristic in which a refractive power thereof in the sagittal direction is larger than a refractive power in the meridional direction, wherein one lens surface of the fourth lens unit is an anamorphic surface.
 29. A telecentric fθ lens system as claimed in claim 28, wherein the fourth lens unit includes a positive lens component, a negative lens component and a positive lens component in order from the object field side.
 30. A telecentric fθ lens system as claimed in claim 28, wherein the fourth lens unit includes two positive lens components, a negative lens component and a positive lens component in order from the object field side.
 31. A telecentric fθ lens system as claimed in claim 28, further fulfilling the following conditions:0≦f_(M) /r_(A) <1 0.6<f_(M) /r_(B) <1 0≦-f_(M) /r_(C) <1 0.4<f_(M) /d_(D) <0.7 wherein f_(M) is a total focal length of the lens system in the meridional direction, r_(A) is a radius of curvature of the image field side surface of the negative lens component in the first lens unit, r_(B) is a radius of curvature of the object field side surface of the positive lens component in the third lens unit, r_(C) is a radius of curvature of the object field side surface of the negative lens component in the fourth lens unit, and d_(D) is an axial distance of the whole lens system.
 32. A telecentric fθ lens system as claimed in claim 28, further fulfilling the following conditions:0≦f_(M) /r_(A) <1 0.6<f_(M) /r_(B) <1 0≦-f_(M) /r_(C) <1 0.4<f_(M) /d_(D) <0.6 wherein f_(M) is a total focal length of the lens system in the meridional direction, r_(A) is a radius of curvature of the image field side surface of the negative lens component in the first lens unit, r_(B) is a radius of curvature of the object field side surface of the positive lens component in the third lens unit, r_(C) is a radius of curvature of the object field side surface of the negative lens component in the fourth lens unit, and d_(D) is an axial distance of the whole lens system.
 33. A telecentric fθ lens system as claimed in claim 28, further fulfilling the following conditions:f_(s) <f_(M) 0.4<-β_(s) <0.8wherein: f_(s) =a total focal length of the lens system in the sagittal direction, f_(M) =a total focal length of the lens system in the meridional direction, and β_(s) =a magnification in the sagittal direction. 